Veterans Day —which began as Armistice Day in 1918, celebrating the end of World War I — is America's way of honoring the men and women who have served in defense of the country in decades of war.

Here are some iconic images of the American GI.

Photo: ASSOCIATED PRESS

Veterans Day —which began as Armistice Day in 1918, celebrating...

Veterans Day —which began as Armistice Day in 1918, celebrating... Photo-3714414.52195 - SFGate

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A view of a soldier using a Springfield rifle, 1938.

Photo: William Vandivert, Time & Life Pictures/Getty Image

A view of a soldier using a Springfield rifle, 1938.

A view of a soldier using a Springfield rifle, 1938. Photo-5429783.52195 - SFGate

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NY National Guardsman Private T. P. Loughlin of 69th New York National Guard Regiment, kissing his little child goodbye as he bids farewell to family before reporting to training camp during WWI, 1917.

American soldiers using a Sherman tank for cover as it and they advance on Japanese positions during the fight to take Bougainville, 1944.

Photo: Time Life Pictures, Time & Life Pictures/Getty Image

American soldiers using a Sherman tank for cover as it and they...

American soldiers using a Sherman tank for cover as it and they... Photo-5429803.52195 - SFGate

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U.S. troops prepare to land on D-Day.

Photo: AP

U.S. troops prepare to land on D-Day.

U.S. troops prepare to land on D-Day. Photo-3714419.52195 - SFGate

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An American soldier sits in a foxhole and grimly smokes a cigarette during a break in World War II combat, Germany, 1944. He holds an M3 submachine gun under his arm.

Photo: John Florea., Time & Life Pictures/Getty Image

An American soldier sits in a foxhole and grimly smokes a cigarette...

An American soldier sits in a foxhole and grimly smokes a cigarette... Photo-5429808.52195 - SFGate

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Major George Spencer Roberts, in training for US Army Air Corps 99th Pursuit Squadron.

Photo: Gabriel Benzur, Time & Life Pictures/Getty Image

Major George Spencer Roberts, in training for US Army Air Corps...

Major George Spencer Roberts, in training for US Army Air Corps... Photo-5429787.52195 - SFGate

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Soldiers posing in the fields with ammunition shells with the inscription reading "Happy Easter Hitler," 1945.

Photo: Herbert Orth, Time & Life Pictures/Getty Image

Soldiers posing in the fields with ammunition shells with the...

Soldiers posing in the fields with ammunition shells with the... Photo-5429798.52195 - SFGate

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The cover of Life magazine features a photo of American pilot trainee Shirley Slade, in a flight suit and pigtails, as she sits on the wing of her Army trainer at Avanger Field, Sweetwater, Texas, July 19, 1943.

Photo: Peter Stackpole, Time & Life Pictures/Getty Image

The cover of Life magazine features a photo of American pilot...

The cover of Life magazine features a photo of American pilot... Photo-5429810.52195 - SFGate

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A sailor on leave saying goodbye to his family as his leave comes to an end, 1942

Photo: J. R. Eyerman, Time & Life Pictures/Getty Image

A sailor on leave saying goodbye to his family as his leave comes...

A sailor on leave saying goodbye to his family as his leave comes... Photo-5429789.52195 - SFGate

US troops disembarking from a landing craft to wade through surf towards beachhead in the days following the invasion of Normandy, 1944.

Photo: Time Life Pictures, Time & Life Pictures/Getty Image

US troops disembarking from a landing craft to wade through surf...

US troops disembarking from a landing craft to wade through surf... Photo-5429800.52195 - SFGate

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A U.S. Marine is seen as he chats with his scouting dog, at Guam, in August 1944, during World War II. The dogs were used to track down Japanese soldiers hidden in caves or jungle strongholds, and for running messages.

Photo: ASSOCIATED PRESS

A U.S. Marine is seen as he chats with his scouting dog, at Guam,...

A U.S. Marine is seen as he chats with his scouting dog, at Guam,... Photo-3714420.52195 - SFGate

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African-American soldiers during World War II.

Photo: David E. Scherman, Time & Life Pictures/Getty Image

African-American soldiers during World War II.

African-American soldiers during World War II. Photo-5429788.52195 - SFGate

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U.S. Marines of the 28th Regiment, 5th Division, raise the American flag atop Mt. Suribachi, Iwo Jima, on Feb. 23, 1945. Strategically located only 660 miles from Tokyo, the Pacific island became the site of one of the bloodiest, most famous battles of World War II against Japan.

Photo: JOE ROSENTHAL, AP

U.S. Marines of the 28th Regiment, 5th Division, raise the American...

U.S. troops in the Pacific islands continued to find enemy holdouts long after the main Japanese forces had either surrendered or disappeared. Guam was considered cleared by August 12, 1944, but parts of the island were still dangerous half a year later. Here, patrolling Marines pass a dead Japanese sniper. These Marines may belong to the Fifty-second Defense Battalion, one of two black units sent to the Pacific.

Photo: CHARLES P. GORRY, ASSOCIATED PRESS

U.S. troops in the Pacific islands continued to find enemy holdouts...

U.S. troops in the Pacific islands continued to find enemy holdouts... Photo-3714426.52195 - SFGate

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U.S. troops display captured Japanese flags during World War II.

Photo: AP

U.S. troops display captured Japanese flags during World War II.

U.S. troops display captured Japanese flags during World War II. Photo-3714427.52195 - SFGate

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Pfc. Paul Ison from the 6th Marine Division dashes forward through Japanese machine-gun fire while crossing a draw on Okinawa, May 10, 1945. After the Marines sustained more than 125 casualties in eight hours in the attempt to cross this draw, the men named the location "Death Valley."

A jubilant American sailor clutching a white-uniformed nurse in a back-bending, passionate kiss as he vents his joy while thousands jam Times Square to celebrate the long awaited-victory over Japan, 1945.

Photo: Alfred Eisenstaedt, Time & Life Pictures/Getty Image

A jubilant American sailor clutching a white-uniformed nurse in a...

A jubilant American sailor clutching a white-uniformed nurse in a... Photo-5429812.52195 - SFGate

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Two American soldiers line up a 3.5 rocket launcher bazooka along the battlefront somewhere in Korea, July 24, 1950.

Photo: ASSOCIATED PRESS

Two American soldiers line up a 3.5 rocket launcher bazooka along...

Two American soldiers line up a 3.5 rocket launcher bazooka along... Photo-3714429.52195 - SFGate

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American soldier writing a letter home while sitting on a mound near his front line bunker on a battle free Sunday, 1951.

Photo: Joseph Scherschel, Time & Life Pictures/Getty Image

American soldier writing a letter home while sitting on a mound...

American soldier writing a letter home while sitting on a mound... Photo-5429806.52195 - SFGate

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Grief-stricken American infantryman whose buddy has just been killed is comforted by a comrade while corpsman in background. methodically fills out casualty tags during a lull in the fighting somewhere near Haktong-ni, 1950.

Two U.S. soldiers are on the alert as they take protection behind stone wall on Korean front near Choyang River in North Korea on June 3, 1951. Cpl. Richard G. Clark, foreground, of Westwood, New Jersey, wears helmet as Pfc. Joseph M. Nadorozny, of 973 east 13th St., Brooklyn, New York, puffs on cigarette.

Photo: E.N.Johnson, AP

Two U.S. soldiers are on the alert as they take protection behind...

Two U.S. soldiers are on the alert as they take protection behind... Photo-3714430.52195 - SFGate

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An unidentified U.S. Army personnel wears a hand lettered "War Is Hell" slogan on his helmet, June 18, 1965, during the Vietnam War. He was with the 173rd Airborne Brigade Battalion on defense duty at Phouc Vinh airstrip in South Vietnam.

Photo: HORST FAAS, AP

An unidentified U.S. Army personnel wears a hand lettered "War Is...

An unidentified U.S. Army personnel wears a hand lettered... Photo-3714431.52195 - SFGate

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SP5 Leon B. Talley, of Tacoma, Wash. keeps his carbine ready as his U.S. Army helicopter approach the rendezvous area of Ap My Qui, South Viet Nam for cleanup operation a against Communist led Viet Cong forces in that Mekong River delta battle zone on April 29, 1962. The U.S. helicopter carried South Viet Nam soldiers for the task of flushing out the Viet Cong.

2nd Lt. R. C. "Rick" Rescorla moves carefully with fixed bayonet through the underbrush in an attack of North Vietnamese sniper pockets outside the American perimeter in the Ia Drang Valley on Nov. 16, 1965 during the Vietnam War. The soldier is a member of one of the hardest hit companies of the 1st Cavalry Division units.

Rescorla, was born in Britain and served in the military there and on the Metropolitan police force before moving to New York and joining the U.S. Army. He was killed in the South Tower of the World Trade Center on September 11, 2001.

Spec. 4 James D. McClafferty of Philadelphia and Pfc. Ted Talley of Marked Tree, Ark., man a machine gun in the ruins of a house near Rach Kien, 22 miles southwest of Saigon, Jan. 2, 1966. Their company, operating in the delta province of Long An, came under fire when they approached a farmhouse at the edge of an abandoned town.

Three U.S. Army nurses serving at a field hospital at Nha Trang, north of the U.S. naval base at Cam Ranh Bay, are seen on July 15, 1965. One of them holds the little dog that Capt. Gladys E. Sepulveda, rear center, found at the beach two days ago after coming ashore from her transport ship.

Photo: ASSOCIATED PRESS

Three U.S. Army nurses serving at a field hospital at Nha Trang,...

Three U.S. Army nurses serving at a field hospital at Nha Trang,... Photo-3714435.52195 - SFGate

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SP4 Nelson A. Parker uses field phone to call for air power as Vietnamese patrol is surrounded by Communist Viet Cong in jungle 20 miles north of Saigon in Vietnam on Feb. 15, 1965. Beside him is Sgt. Lloyd E. Rath. Both were U.S. advisers with the patrol. Eighteen Red guerrillas were killed in the battle. Parker’s parents live in Paul Smiths, New York. Rath’s wife lives in Ephrata, Pa.; his mother in Jamestown, North Dakota.

Photo: Anonymous, AP

SP4 Nelson A. Parker uses field phone to call for air power as...

SP4 Nelson A. Parker uses field phone to call for air power as... Photo-3714436.52195 - SFGate

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Paratroopers of the U.S. 173rd Airborne Brigade man a machine gun position after they advance into a rubber plantation near Bien Hoa air base, 12 miles northeast of Saigon in Vietnam on May 10, 1965. The plantation area had been frequency used by Viet Congs for ambush.

Commanders of two U.S. Marine companies who had been surrounded for two days by the North Vietnamese 324 Division eight miles south of the demilitarized zone, pause for a cigarette after other American units came to their aid, Sept. 20, 1966. They are 1st Lt. Daniel McMahon , left, of Oceanside, N.Y., who leads Delta Co., and Capt. Ronald Frederickson, South Sioux City, Neb, commander of Bravo Co. Sept. 20, 1966.

Photo: ASSOCIATED PRESS

Commanders of two U.S. Marine companies who had been surrounded for...

Commanders of two U.S. Marine companies who had been surrounded for... Photo-3714438.52195 - SFGate

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Two American paratroopers keep a sharp eye out for guerrillas and snipers as they patrol the jungle in D zone, some 20 miles northeast of Bien Hoa, Vietnam on May 31, 1965. They are members of an artillery battery and a battalion of paratroopers from the U.S. 173rd Airborne Brigade which were lifted by helicopter in the zone along a stronghold of the Viet Cong.

Photo: Horst Faas, AP

Two American paratroopers keep a sharp eye out for guerrillas and...

Two American paratroopers keep a sharp eye out for guerrillas and... Photo-3714439.52195 - SFGate

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Released prisoner of war Lt. Col. Robert L. Stirm is greeted by his family at Travis Air Force Base in Fairfield, Calif., as he returns home from the Vietnam War, March 17, 1973. In the lead is Stirm's daughter Lori, 15; followed by son Robert, 14; daughter Cynthia, 11; wife Loretta and son Roger, 12.

Photo: SAL VEDER, AP

Released prisoner of war Lt. Col. Robert L. Stirm is greeted by his...

Released prisoner of war Lt. Col. Robert L. Stirm is greeted by... Photo-3714440.52195 - SFGate

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Bundled against the chill a U.S. Marine reports to his headquarters on a radiotelephone during operation Kentucky near the demilitarized zone in South Vietnam on Dec. 11, 1967. Monsoon rains and temperatures that drop into the 40s and 50s at night make life miserable for the U.S. soldiers in the Northern provinces.

Photo: Dag VAn Phuoc, AP

Bundled against the chill a U.S. Marine reports to his headquarters...

Bundled against the chill a U.S. Marine reports to his headquarters... Photo-3714441.52195 - SFGate

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U.S. Sgt. Adolph J. Breecher of Saginaw, Michigan, fighting in the Vietnam War in 1966, is shown smoking a cigarette.

American soldiers are dropped off by U.S.Army helicopters to join South Vietnamese ground troops to advance in an attack on a Viet Cong camp 18 miles north of Tay Ninh, northwest of Saigon near the Cambodian border, in March 1965 during the Vietnam War.

Photo: HORST FAAS, AP

American soldiers are dropped off by U.S.Army helicopters to join...

American soldiers are dropped off by U.S.Army helicopters to join... Photo-3714443.52195 - SFGate

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U.S. soldier communicating during the Vietnam War in Saigon in an undated photo.

Photo: Eddie Adams, AP

U.S. soldier communicating during the Vietnam War in Saigon in an...

U.S. soldier communicating during the Vietnam War in Saigon in an... Photo-3714444.52195 - SFGate

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An infantryman of the U.S. 25th Division rushes for cover as he comes under sniper fire near the village of Rach Kien, 20 miles southwest of Saigon in Vietnam's Mekong Delta, in 1967 during the Vietnam War.

Photo: ASSOCIATED PRESS

An infantryman of the U.S. 25th Division rushes for cover as he...

An infantryman of the U.S. 25th Division rushes for cover as he... Photo-3714445.52195 - SFGate

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Pfc. James F. Duro of Boston, Mass., a member of C Company, 173rd Airborne Brigade, lies exhausted on a canal dike in the swampland of the Mekong Delta near Bao Trai, about 20 miles west of Saigon, on Jan. 4, 1966. An hour Duro survived friendly fire from a misdirected artillery bombardment that, in addition to enemy fire, left fellow soldiers dead and wounded.

Photo: Horst Faas, AP

Pfc. James F. Duro of Boston, Mass., a member of C Company, 173rd...

Pfc. James F. Duro of Boston, Mass., a member of C Company, 173rd... Photo-3714446.52195 - SFGate

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U.S. soldier communicating during the Vietnam War in Saigon in an undated photo.

Photo: Eddie Adams, AP

U.S. soldier communicating during the Vietnam War in Saigon in an...

U.S. soldier communicating during the Vietnam War in Saigon in an... Photo-3714447.52195 - SFGate

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The cover of Life magazine shows a pair of American soldiers as they carry a wounded comrade to safety, accompanied by the headline 'Deeper into the Vietnam War,' Vietnam, July 2, 1965.

Photo: Bill Eppridge, Time & Life Pictures/Getty Image

The cover of Life magazine shows a pair of American soldiers as...

The cover of Life magazine shows a pair of American soldiers as... Photo-5429813.52195 - SFGate

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Betty Jo Reed, shown during World War II, is among just 650 or so surviving members of the Women's Airforce Service Pilots Program. Four WASPs recently got together in Harbor Springs, Mich., for a reunion, recalling how they blazed trails across the sky.

Photo: BETTY JO REED, ASSOCIATED PRESS

Betty Jo Reed, shown during World War II, is among just 650 or so...

Betty Jo Reed, shown during World War II, is among just 650 or so... Photo-3714448.52195 - SFGate

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Pfc. Eugene Cabbagestalk of Pittsburgh, Pa., pushes back his helmet to wipe the sweat from his face in South Vietnam, August 1966. Cabbagestalk was killed in Vietnam the following January.

Photo: Henri Huet, AP

Pfc. Eugene Cabbagestalk of Pittsburgh, Pa., pushes back his helmet...

A soldier of the 25th Infantry Division, coated with sweat and grime, patrols thick jungle near the Cambodian border, Nov. 26, 1966. B-52 air strikes had driven out enemy snipers that stalled the unit for three days.

U.S. Staff Sgt. Vernon Larson of Downing, Wisc., shows a beard after nine days in the jungle without a razor, December 1965. His unit had expected to be in the field only two days, and he was traveling light; water had to be dropped into the steamy jungle, about 40 miles north of Saigon.

After their unit landed in the middle of a Viet Cong staging area, medic Pfc. Andrew J. Brown of Chicago draws his pistol while protecting a wounded U.S. paratrooper from sniper fire in the jungle near Thuong Lang, about 10 miles northeast of Bien Hoa, June 24, 1965. Brown and another medic crawled through the jungle to treat the paratrooper while a live grenade lay nearby.

Photo: AP

After their unit landed in the middle of a Viet Cong staging area,...

After their unit landed in the middle of a Viet Cong staging area,... Photo-3714536.52195 - SFGate

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Capt. Donald R. Brown of Annapolis, Md., advisor to the 2nd Battalion of the 46th Vietnamese regiment, dashes from his helicopter to the cover of a rice paddy dike during an attack on Viet Cong in an area 15 miles west of Saigon on April 4, 1965 during the Vietnam War. Brown's counterpart, Capt. Di, commander of the unit, rushes away in background with his radioman. The Vietnamese suffered 12 casualties before the field was taken.

Resting his rifle on his steel helmet to relieve his weary arm, a South Vietnamese soldier plods through deep water of the Mekong River Delta on a mission to ferret out bands of Viet Cong in October 1964. The government troops were ferried into the region by helicopter, but failed to make contact with the enemy after wading through acres of water and mud.

Photo: AP

Resting his rifle on his steel helmet to relieve his weary arm, a...

Resting his rifle on his steel helmet to relieve his weary arm, a... Photo-3714533.52195 - SFGate

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The sun breaks through the dense jungle foliage around the embattled town of Binh Gia, 40 miles east of Saigon, in early January 1965, as South Vietnamese troops, apparently joined by U.S. advisers, rest after a cold, damp and tense night of waiting in an ambush position for a Viet Cong attack that didn't come. One hour later, as the possibility of an overnight attack by the Viet Cong disappeared, the troops moved out for another long, hot day hunting the elusive communist guerrillas in the jungles.

Photo: AP

The sun breaks through the dense jungle foliage around the...

The sun breaks through the dense jungle foliage around the... Photo-3714532.52195 - SFGate

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Wounded Marine Gunnery Sargeant Jeremiah Purdie (C) is led past stricken comrades after fierce firefight for control of Hill 484, south of DMZ in South Vietnam, 1966.

US Army Special Forces Capt. Vernon Gillespie contacting his base camp by radio while Vietnamese soldiers burn down a Vietcong hideout, 1964.

Photo: Larry Burrows, Time & Life Pictures/Getty Image

US Army Special Forces Capt. Vernon Gillespie contacting his base...

US Army Special Forces Capt. Vernon Gillespie contacting his base... Photo-5429802.52195 - SFGate

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U.S. Marines of the 7th Fleet's special landing team, the 1st Battalion, 26th Marines, crouch on a dirt trail with a 3.5 inch rocket launcher about one mile (2000 meters) south of the demilitarized zone (DMZ) as they respond to sniper fire during Operation Prairie against the North Vietnamese 324B Division, September 1966.

Photo: AP

U.S. Marines of the 7th Fleet's special landing team, the 1st...

U.S. Marines of the 7th Fleet's special landing team, the 1st... Photo-3714531.52195 - SFGate

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Members of the U.S. Army 3rd Brigade 101st Airborne Division (Air Assault) "The Rakkasans", scan the northwest perimeter of the American compound at Kandahar International Airport on Friday Jan. 18, 2002. U.S. soldiers replaced Marines in key defense posts at the base Friday.

Photo: MARCO DI LAURO, ASSOCIATED PRESS

Members of the U.S. Army 3rd Brigade 101st Airborne Division (Air...

Members of the U.S. Army 3rd Brigade 101st Airborne Division (Air... Photo-3714451.52195 - SFGate

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A U.S. Marine Harrier ground crew member, who would not be identified, shoots a souvenir picture as his Harrier squadron prepares to leave Dhahran, Saudi Arabia, Friday, March 15, 1991, for their return to the Cherry Point, N.C., Marine Air Station.

Photo: Bob Jordan, ASSOCIATED PRESS

A U.S. Marine Harrier ground crew member, who would not be...

A U.S. Marine Harrier ground crew member, who would not be... Photo-3714452.52195 - SFGate

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U.S. soldier rests while on guard at a relay station in the Saudi Arabian dessert during operation Desert Shield, November 9, 1990.

Photo: DIETER ENDLICHER, AP

U.S. soldier rests while on guard at a relay station in the Saudi...

U.S. soldier rests while on guard at a relay station in the Saudi... Photo-3714453.52195 - SFGate

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U.S. Army Sgt. John Cobb of Newport Beach, Calif., keeps his dog, J.C., warm inside his coat while waiting for the arrival of the U.S. command ship, the U.S.S. LaSalle, in Kuwait City on Tuesday, March 12, 1991.

Photo: Greg Gibson, ASSOCIATED PRESS

U.S. Army Sgt. John Cobb of Newport Beach, Calif., keeps his dog,...

U.S. Army Sgt. John Cobb of Newport Beach, Calif., keeps his dog,... Photo-3714454.52195 - SFGate

Sgt. Dave Carbary, 24, center, of Sterling Heights, Mich., with the U.S. Army's 4th Brigade Combat Team, 101st Airborne Division out of Fort Campbell, Ky., waits with fellow soldiers to have his luggage checked by U.S. Customs at the Transit Center in Manas, Kyrgyzstan, while continuing home after leaving Afghanistan upon completing a deployment, Monday, Aug. 8, 2011.

An Iraqi boy watches as a U.S. army soldier from B Company, 1st Battalion, 23rd Infantry Regiment lights up a cigarette as members of his unit take a rest after a foot patrol in Baghdad's Shiite enclave of Sadr City, Iraq, Saturday, March 17, 2007.

Photo: MARKO DROBNJAKOVIC, ASSOCIATED PRESS

An Iraqi boy watches as a U.S. army soldier from B Company, 1st...

An Iraqi boy watches as a U.S. army soldier from B Company, 1st... Photo-3714457.52195 - SFGate

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US soldiers read verses as they celebrate Easter with a sunrise service at Camp Victory, in Baghdad, Iraq, Sunday, March 23, 2008.

Photo: DUSAN VRANIC, ASSOCIATED PRESS

US soldiers read verses as they celebrate Easter with a sunrise...

US soldiers read verses as they celebrate Easter with a sunrise... Photo-3714458.52195 - SFGate

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U.S. Marines play football in Karabilah, an Iraqi town near the Syrian border, Thursday, Nov. 24, 2005.

Photo: JACOB SILBERBERG, ASSOCIATED PRESS

U.S. Marines play football in Karabilah, an Iraqi town near the...

U.S. Marines play football in Karabilah, an Iraqi town near the... Photo-3714459.52195 - SFGate

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A string of bullets hangs on the neck of US Army soldier PFC Jean-Paul Desculline , of Miami, Florida, from 1-320th Alpha Battery, 2nd Brigade of the 101st Airborne Division, at COP Nolen, in the volatile Arghandab Valley, Kandahar, Afghanistan, Sunday, July 25, 2010.

Photo: Rodrigo Abd, ASSOCIATED PRESS

A string of bullets hangs on the neck of US Army soldier PFC...

A string of bullets hangs on the neck of US Army soldier PFC... Photo-3714460.52195 - SFGate

Spc. John Lundy, right, and Spc. Matthew Sturgill, obscured, leap into the arms of PFC Devin Horton, left, Friday, Dec. 23, 2011, at Camp Atterbury in Edinburgh, Ind., as 109 members of the 1st Battalion, 149th Infantry, National Army Guard, prepare to board a bus home to Kentucky and join their families for the holidays.